# How would you assign an oxidation number to HCl?

Oct 26, 2015

How would I assign individual oxidation numbers to the constituent atoms of hydrochloric acid? Attend.

#### Explanation:

We have a $H - C l$ molecule; when we break the bond (conceptually!) the 2 bonding electrons are assumed to go to the most electronegative atom, which is $C l$. So we get ${H}^{+}$ and $C {l}^{-}$. By definition, the oxidation number is the charge left on the central atom when all of the bonding electrons pairs are broken. Therefore, oxidation number of $H$ $=$ $+ I$, and oxidation number of $C l$ $=$ $- I$.

Try doing this for $F - C l$, ${H}_{2} O$, and $C {F}_{4}$.

Oct 26, 2015

The oxidation number of hydrogen is $\text{+1}$ and the oxidation number of chlorine is $\text{-1}$.

#### Explanation:

The sum of oxidation numbers in a compound is zero. So the oxidation number of the compound $\text{HCl}$ is zero.

In a compound, hydrogen has an oxidation number of $\text{+1}$.

Since the sum of the oxidation numbers of hydrogen and chlorine must equal zero, the oxidation number of chlorine must be $\text{-1}$.

$1 \left(+ 1\right) + 1 \left(- 1\right) = 0$

$\text{H"^(+1)"Cl"^(-1)}$